Sorry, did not understand your inquiry well, but if the zip is not designed and made to be waterproof, don't think you can make it that way. The teeth by their very nature will admit water when closed, so the zipper tape is waterproof, and designed to close behind the teeth with a tight seal.
They work fairly well, but ever since using them on packs, I've also continued to design in zipper flap covers just like those that packs used to have before the waterproof zippers came into use. This has worked very well, and I've had no leakage into pockets or the pack bag when hiking in heavy and extended rains. This is with the last two packs, one of a ripstop nylon with a thick coating, formerly sold by OWF as "storm," and the other of Spectra gridstop, formerly sold by Seattle Fabrics. Oddly, the OWF stuff had no DWR on the outer, despite the thick inner coating, and had to be drenched on the outside with Tectron before use. It wasn't very abrasion resistant, either.
But the waterproofness on the gridstop began to fail a little last summer after several years, as did the 1.9 oz. silnylon used for the stuff bags and extension sleeve. It could be the seam sealant just dried up, but judging from the location of the slight leaks, I think it may have been the coating on the material itself
So, as noted today on the GEAR forum, the next pack will be 5 oz. Xpac, VX07, and I expect the waterproofness will last longer on this one. Don't know why anyone would not want a waterproof pack. The weight penalty is only a few ounces, and the convenience is super. Will still use a drybag when on the water, though.
EDIT: Well, duh, so the Talon is a pack, not a zipper. Without trying to source the Osprey materials, they probably are, as already mentioned in another post, urethane coated. If you think they need more coating, there are urethane coating products, like SeamGrip Tent Sure, tent floor sealant.